Most to least Mormon states (and Salt Lake found to be most Christian city in U.S.)

--The researchers found Utah to be the most Mormon state with close to 70 percent identifying as Mormon adherents. Nearly one in three Mormons are in the state of Utah. The researchers found the District of Columbia (just the district) to be the least Mormon state with only about 0.07 percent identifying as Mormon adherents.

The researchers define adherents to be those with an affiliation to a congregation including children, members and attendees who are not members, and believe that the adherent measure is the most complete and comparable across religious groups.Congregations are defined as groups of people who meet regularly at a pre-announced time and location.

More than 6.1 million Mormon adherents and 13,601 congregations were reported in 1,873 counties. The largest concentration of Mormons in the United States is in the mountain region of the West where more than 5 percent of the population identified as a Mormon. The smallest concentration of Mormons were found in the Northeast and pockets in the South.

Similarly, the most dense concentration of Mormon congregations is found in the Western region of the country. In stark contrast, the Midwest, most of the South and Northeast reported very few to almost zero congregations.

As the map below shows, compared to the year 2000, most of the West reported minor change in percentage of Mormon adherents. Many regions in the South and Midwest reported major gains in Mormon population in some counties, and major losses in others.